Sliding bolt rack mechanism



Oct. 21, s QAS SLIDING BOLT RACK MECHANISM Filed Sept. 19, 1950 v 3Sheets-Sheet l IE Z I N V EN TOR. firm a4 \7. Kama/z Oct. 21, 1952 A. s.CASWELL SLIDING: BOLT RACK MECHANISM 3 Sheets-Sheet 2 Filed Sept. 19,1950 ICE--15 -riOJ I N V EN TOR. $127M? 5. dam/5a.

BY WJW Oct; 21, 1952 A. s. CASWELL SLIDING BOLT RACK MECHANISM- 3Shets-Sheet: 3

Fild Sept. 19, 1950 I N V EN TOR flan/w? .5 Unswaz W #921,

Patented Oct. 21, 1952 SLIDING BOLT RACK MECHANISM Arthur S. Caswell,Philadelphia, Pa., assignor to I-T-E Circuit Breaker Company,Philadelphia, Pa., a corporation of Pennsylvania Application September19, 1959, Serial No. 185,572

9 Claims.

My present invention is an improvement of the racking mechanismdisclosed in the circuit breaker described in application Serial No.721,648, of Joseph D. Wood, filed January 11, 1947, and applicationSerial No. 757,356, of Elmer Goessel, filed June 7, 1947, and relatesspecifically to .the means for securing the racking bar to thestationary cubicle in order to provide an appropriate anchor for theracking mechanism.

My present invention is also an improvement of the racking mechanismdescribed in my application Serial No. 159,598, filed May 2, 1950,relating also to an improvement in the means for securing the rackingbar to the cubicle.

In the latter application, a grounding device is shown which is intendedto be racked into and out of a cubicle to replace a circuit breaker. Thegrounding device has a racking bar which is movable by a screw threadwith respect to the grounding device.

Thus, when the racking bar of the grounding device is anchored in thecubicle, the relative movement of the racking bar with respect to thegrounding device causes the grounding device to move in or out of thecubicle owing to the fact that the racking bar is secured to saidcubicle.

The specific method of obtaining this anchor is shown in my aforesaidapplication Serial No. 159,598 as a pair of movable latching means inthe cubicle which engage the ends of the racking bar.

In the above-mentioned applications, Serial Nos. 721,648 and 757,356, nospecific means is shown for anchoring the end of the racking bar, butlocks of the type shown in application Serial No. 159,598 may be usedand have, in fact, been used commercially.

The utilization of such additional locks which require manipulations atthe side of the cubicle when the circuit breaker or grounding device, asthe case may be, is introduced into the cubicle in order to anchor theracking bar with respect to the cubicle creates some difficulty in thatthe operator must manipulate these locks on opposite sides and does notoperate them from the front.

In addition, the utilization of such additional movable anchoringmembers in'the cubicle requires the placement of such movable parts onthe stationary cubicle element and the exact registry of these movableparts with the racking bar.

My invention is, therefore, directed to a novel racking bar having asliding bolt interlock at each end arranged to engage a flange of thecubicle. The sliding bolt interlock is so arranged 2 that manipulationof a handle at the front of the circuit breaker, the grounding device,or other element which is to be introduced into the cubicle between thelocked and unlocked position will cause the sliding bolt to move out tolocking engagement behind the flange or in out of locking engagementbehind the flange.

In applying my invention to a circuit breaker of the type disclosed inapplication Serial No. 721,648, the structure of the circuit breakertherein shown and the structure of the racking in mechanism thereinshown need not be changed in any manner.

It only requires a change in the transverse racking bar 400 (Figs. 1,10, 11 and 12) of the mechanism shown in the said application.

By the utilization of my novel racking bar, the circuit breakermechanism is interlocked with the racking bar so that the circuitbreaker cannot be introduced into the cubicle unless the circuit breakermechanism is in the test position.

After the circuit breaker has been introduced into the cubicle and theracking bar locked with the cubicle, then and only then may the circuitbreaker mechanism be racked into the operating position. After thecircuit breaker is racked into the operating position, it cannot bepulled out of the cubicle until it is racked out to the test position.

A primary object of my invention, therefore, is the pro-vision of anovel racking bar so arranged as to enable a circuit breaker, groundingdevice or other similar piece of electrical apparatus to be racked inand out of the test and operating position in a cubicle.

Another object of my invention is the provision of a novel racking barwith a sliding bolt interlocked with a flange or other retaining elementin a cubicle.

Another and corollary object of my invention is the provision of aracking-in mechanism which will co-act with an interlocking means insuch a manner as to remove necessity of holding adjustments betweenstationary structure and removable element to close and exacttolerances. Such an interlocking means is described in a pendingapplication, Serial No. 135,573.

Another object of my invention is the provision of a novel meansinterlocking the racking bar and the racking mechanism in such mannerthat the circuit breaker cannot be inserted in the cubicle unless it isin the racked out or test posi tion, and it cannot be withdrawn from thecubicle unless it is in the racked out or test position.

The foregoing and many other objects of invention will become apparentin the following description and drawings in which:

Figure 1 is a view in perspective of my novel racking bar showing thesame in unlocked position.

Figure 2 is a View corresponding to that of Figure 1 showing the rackingbar in the locked position.

Figure 3 is a view in perspective showing the racking bar of myinvention mounted on the circuit breaker of application Serial No.721,648 with the circuit breaker in a position out of the cubicle andwith the racking bar in the unlocked position of Figure 1.

Figure 4 is a top plan view partly in cross-section of the rackingmechanism of Figures 1 to 3.

Figure 5 is a front view partly in cross-section of the rackingmechanism of Figures 1 to 3.

Referring to the figures, the racking bar 400 corresponds in locationand actual function to the racking bar 400 shown in Figures 1, 10, 11and 12 of application Serial No. 721,648.

Since the racking mechanism which is actually used is shown in theheretofore referred application Serial No. 721,648 and is fullydescribed therein, a separate specific description of the rackingmechanism which moves the circuit breaker with respect to its support isnot contained herein but rather may be regarded as incorporated byreference herein.

While the specific racking bar 400 of the present invention maycooperate with other racking mechanisms, it is preferred that it be usedwith the racking mechanism of the said application Serial No. 721,648and with the circuit breaker shown in the said application.

The racking bar 400 forming a part or" the circuit breaker mechanism asshown in the above identified application is provided with an opening lwhich is provided with internal screw threads which engages the threadsof racking screw I I. Racking screw I I is rotatable and such rotationmoves the bar 400 along the racking screw II.

Racking bar 400 and screw I I are supported on the circuit breaker bythe engagement of screw II with bearing I2 on the circuit breakermechanism. The outer end I of screw I I is provided with a handle orwith a squared end I5 or other deformation which will enable a handle tobe attached for the purpose of rotating the screw I I.

Rotation of end I5 of screw II will, of course, cause the screw I I torotate and to move the bar 400 longitudinally along the screw II in adirection determined by the direction of rotation of screw II. Thebearing i2 is a thrust bearing to provide against the longitudinalforces of the screw II.

The movement of the bar 400 along the screw II causes it to move withrespect to the breaker.

Should the racking'bar be held stationary, then rotation of screw IIcauses the screw II and the circuit breaker mechanism mounted therein tobe racked in or out of the operating position.

The racking bar 400 is provided with extensions 20 and 2I on each side,the said extensions having the cylindrical openings 22 and 23,respectively, extending parallel to the racking bar 400.

Sliding bolts 24 and 25 are operable in the openings 22 and 23, each ofthe sliding bolts 24 and 25 being, respectively, mounted on flange 2!and .28 of the slide members 29 and 30 of the racking bar 400. Slidemember 29 is slidably positioned on the racking bar 400 by the head 35of a bolt secured to the racking bar 400 and 4 holding the slide member23 through the slot 36 between the head 35 and the racking bar 400.

Slide member 30 is also slidably mounted on the racking bar 400 forlongitudinal movement with respect thereto by bolt 40 and the rotatablethreeway crank 4! having the bifurcated arms 42 and 43 and the handle44. The material of the slide member 30 defining the slot 50 is capturedbe tween the three-way crank 45 and the racking bar 400 so as toposition the slide member 30 thereon.

Slide member 20 is thus supported parallel to the racking bar 400 and insubstantial surface to surface relation therewith by the bolt 35 at oneend and slot 36 while at the other end the sliding bolt 24 in thecylindrical opening 22 of extension 20 of the racking bar 400 supportsand aligns the slide 29.

Slide 30 is similarly aligned by bolt 42 and slot 50 and by sliding bolt25 and opening 23. Slide member 29 has extension 00 secured thereto inany suitable manner as by welding, the said extension being providedwith a pin 6| captured in the end of bifurcated crank element 43.

Slide member 30 is provided with a pin 63 captured in the bifurcatedelement 42 of the crank 4|.

It will thus be seen by a comparison of Figures 1 and 2 that when thehandle and pointer assembly 04 is moved from the upper or unlockedposition to the lower or locked position, the crank member 4| is rotatedclockwise and bifurcated section 42 thereof moves the pin 63 and slide30 to the right, while bifurcated section 43 thereof moves the pin SI,extension 60 and slide 29 to the left.

This, therefore, moves the bolts 25 and 24 on each side outwardly sothat they protrude, respectively, from elements or extensions 20 and 2|of the racking bar 400.

It will thus be seen that after a circuit breaker I00 is placed in thecubicle I02, the movement of handle 44 from the unlocked position ofFigure 1 to the locked position of Figures 2 and 5 will extend the bolts24 and 25 out through openings 22 and 23 so that they extend beyond theends of extensions 20 and 2 I.

The manner in which my novel racking bar is mounted on the circuitbreaker I00 is shown in Figure 3.

The racking mechanism 10 corresponds exactly to the racking mechanismshown in Figs. 1, l0, l1 and 12 of application Serial No. 721,648.

The cubicle I02 is provided on each vertical front edge with a verticalflange I03. When the circuit breaker I00 is wheeled into the cubicleI02, it is moved in until the bolts 24 and 25 are so aligned that whenextended they will extend just behind the flange I03 on each side.

An additional flange I04 is provided with each side spaced inwardly fromflange I 03 and at a location where it will provide a bearing for bolts24 and 25 on each side.

When the bolts 24 and 25 are extended as shown in Figures 2 and 4, theywill thus register in the space between the vertical flange I03 on eachside and the additional flange I04 on each side. The vertical flange I03(Fig, 3), since it is provided in any event for the cubicle, requires noexact registry with the bolts 24 and 25, while the flange I04 may bemade sufficiently long so that no problem of registry will arise withrespect thereto.

After the circuit breaker I00 is wheeled into the cubicle I02 then thehandle 44 is turned from the unlocked position of Figures 1 and 3 to thelocked position of Figures 2 and 5 and bolts 24 and 25 are therebysimultaneously moved as previously described beyond the ends ofextensions 20 and 2I where they will engage in the space between flangesI03 and I04 on each side.

This serves to anchor the racking bar 400 in a horizontal direction tomake it stationary so that when the racking bar 400 is forced to movewith respect to the bearing I2 of the circuit breaker I00, then sincethe racking bar 400 is anchored relative to the cubicle, the circuitbreaker element as a whole must move with respect thereto.

By this means, therefore, a simplified anchoring element is provided forth racking bar 400 which does not require hooks or other manipulatingdevices in the cubicle but requires only the simple manipulation ofhandle 44 from the unlocked to the locked position and vice versa.

While the circuit breaker and rocking bar 400 is out of its cubicle, itis possibl for some one to turn screw I I and thus change the relativeposition of the screw with respect to the circuit breaker and cross bar400.

It is accordingly desirable that additional interlock means be providedso that the circuit breaker I (Fig. 3) cannot be wheeled into thecubicle I02 unless the racking bar 400 and the circuit breaker I00 arein the appropriat position with respect to each other, that is, with thecircuit breaker mechanism racked out or to put it another way, with theracking bar 400 at its innermost position with respect to the circuitbreaker.

Also, it is desirable, and in fact, an important safety factor, toprovide means whereby the racking bar 400 cannot be disengaged from thecubicle I02 to enable a pulling out of the circuit breaker I00 unlessthe circuit breaker I00 has first been racked out by the use of theracking means so that it is completely disconnected from any backconnection studs which are provided between the circuit breaker and thecurrent conducting members leading to the cubicle.

For this purpose, therefore, the circuit breaker is provided with aplatform having downwardly depending flanges 200,20I (see Figs. 1, 2, 4and 5), the lower ends of each flange 200 and I being provided with theslots 202, 203, respectively.

The slide elements 29 and 30 of the racking bar cannot be moved inwardlytoward each other to the unlocked position of Fig. 1 unless the circuitbreaker I00 and hence its flanges 200 and 20I are racked out to aposition where the slots 202 and 203 register opposite to the slidemembers 23 and 30 as shown in Figure 1.

This is so because the slide members 29 and 30 are arranged,respectively, to intersect the lower margins of the flanges 200 and 201,and, therefore, they cannot move in from the locked position of Figure 2to the unlocked position of Fig. 1 unless the circuit breaker has beenracked out so that the slots 202 and 203 register with the ends of theslides 29 and 30.

Thus, the racking bar cannot be placed in the unlocked position with thebolts 24 and 25 withdrawn as shown in Fig. 1 unless the entire circuitbreaker is in a position equivalent co being racked out.correspondingly, if racking screw I I of the circuit breaker is in aposition of being racked-in when the circuit breaker itself is outsidethe cubicle, then the bolts 24 and 25 must be extended.

These bolts will, therefore, engage the outer surfaces of the verticalflanges I03 (Fig. 3) when the circuit breaker is being moved into thecubicle and will prevent the entry of the circuit breaker I00 into thecubicle I02.

Therefore, before the circuit breaker I00 can be introduced in thecubicle I02, the bolts 24 and 25 must be Withdrawn and to accomplishthis operation, the circuit breaker must be racked out or the rackingbar 400 must be at its full inward position with respect to the circuitbreaker I00 which is the equivalent of the racked-out or test positionof the circuit breaker I00.

After the circuit breaker I00 has been properly moved into the cubicleI02 with the bolts 24 and 2-5 withdrawn to permit the entry, theracking" mechanism cannot be operated to move the circuit breaker I00into the operating position until the racking bar 400 has been locked bythe moving down of handle 44.

This is so because any attempt to rack in the circuit breaker once it isintroduced into the cubicle but not locked will result in relativemovement of the racking bar 400 with respect to the circuit breakerelement I00 but because of the relatively greater inertia of the circuitbreaker I00 the racking bar will be moved by the rotation of the rackingscrew I I.

Consequently, before the racking-in movement is begun, the handle 44must be pressed down to extend the bolts 24 and 25 into a recess oraperture mounted on the track (not shown). This serves to lock andanchor the racking bar 400 with respect to the cubicle I02 and at thesame time allows the slides 29 and 30 to emerge freely from the slots202 and 203.

The screw II may now be turned to rack the circuit breaker I00 in fromthe test position to the operating position. At the initiation of thisracking-in movement, the flanges 200 and 20I move inwardly to the rearof the cubicle and hence slots 202 and 203 therein move inwardly towardthe rear of the cubicle so that the solid material at the lower end ofthe margin of flanges EM and 200 is in the path of movement of theslides 29 and 30.

Consequently, the handle 44 cannot be raised to the unlocked positionand bolts 24 and 25 cannot be withdrawn from looking position while thecircuit breaker is even partially racked-in owing to the fact that theinward movement of slides 29 and 30 is impeded by the lower margin ofthe flanges 200 and 20! and also owing to the fact that the slots 202and 203 have been displaced from the slides 29 and 30.

Thus, while the circuit breaker I00 is racked into operative position orat any position between the operative position and the fully racked outor test position, it cannot be released and the racking bar is fullylocked in.

Thus, no accidental withdrawal of the circuit breaker I00 from thecubicle I02 can occur while the circuit breaker I00 is in the operativeposition and the withdrawal of the circuit from the cubicle I02 cannotoccur until the fully racked out position or test position of thecircuit breaker is reached.

By this means, therefore, a simplified racking bar is provided withsimplified sliding bolt means for connecting the racking bar to thecubicle while at the same time an efficient interlock is provided toprevent the insertion of the circuit breaker in the cubicle unless thecircuit breaker is fully racked out to the test position; also toprevent the removal of the circuit breaker from the cubicle unless thecircuit breaker is first fully racked out to the test position.

In the foregoing I have described my invention solely in connection withspecific illustrative embodiments thereof. Since many variations andmodifications of my invention will now be obvious to those skilled inthe art, I prefer to be bound not by the specific disclosures hereincontained but only by the appended claims.

I claim:

1. In a racking mechanism for circuit breakers; a cubicle for housing acircuit breaker; a racking bar having an opening; a racking screwextending through said opening; a circuit breaker mechanism carryingsaid racking screw and mountable for movement with said racking screw;said racking screw having screw threads engaging with threads in saidopening to permit relative movement of said racking screw and thecircuit breaker with respect to said racking bar when said racking screwis rotated; a slide member for each end of said racking bar, each slidemember having a slotted end; a bolt extending from each end of saidracking bar into the slot of the adjacent slide member; a three-waycrank mounted adjacent one of said slide members, said crank having alock and unlock position and a pair of bifurcated crank extensionsthereon, a pin connected to said one of said slide members and extendingthrough one of the bifurcated crank extensions, a connecting rodconnected at one end of the other of said slide members and having a pinat its other end extending through the other of said pair of bifurcatedcranks, said three way crank when rotated causing movement of said slidebars in a direction longitudinally of said racking bars said slide barsmoving in opposite directions; a pin extending from each of said slidebars; a bearing mounted on the side walls of said cubicle for receivingsaid slide member pins when said slide bars have been movedlongitudinally away from said racking bar in response to the rotation ofsaid threeway crank to its locked position; said pins when extended intosaid bearings acting to anchor said racking bar so that when said screwis rotated. said screw and the circuit breaker carrying said screw ismoved relative to said racking bar and cubicle; downwardly extendingflanges mounted on said circuit breaker, said flanges being in the pathof movement of said slide members; said flanges having slots throughwhich slide bars can move to unlocked position when said circuit breakerhas been moved to its racked out position, and a flange on said cubiclefor preventing entry of said circuit breaker into said cubicle whilesaid slide members are in extended or locked position.

2. In a racking mechanism for circuit breakers; a cubicle for housing acircuit breaker; a racking bar having an opening; a racking screwextending through said opening; a circuit breaker mechanism carryingsaid racking screw and mountable for movement with said racking screw;said racking screw having screw threads engaging with threads in saidopening to permit relative movement of said racking screw and thecircuit breaker with respect to said racking bar when said racking screwis rotated; a slide member for each end of said racking bar, each slidemember having a slotted end; a bolt extending from each end of saidracking barinto the slot of the adjacent slide member; a three-way crankmounted adjacent one of said slide members, said crank having a lock andunlock posi tion and a pair of bifurcated crank extensions thereon, apin connected to said one of said slide members and extending throughone of the bifurcated crank extensions, a connecting rod connected atone end of the other of said slide members and having a pin at its otherend extending through the other of said pair of bifurcated cranks, saidthree way crank when rotated causing movement of said slide bars in adirection longitudinally of said racking bars, said slide bars moving inopposite directions; a pin extending from each of said slide bars; abearing mounted on the side walls of said cubicle for receiving saidslide member pins when said slide bars have been moved longitudinallyaway from said racking bar in response to the rotation of said three-waycrank to its locked position; said pins when extended into said bearingsacting to anchor said racking bar so that whensaidscrew is rotated, saidscrew and the circuit breaker carrying said screw is moved relative tosaid racking bar and cubicle; downwardly extending flanges mounted onsaid circuit breaker, said flan es being in the path of movement of saidslide members; said flanges having slots through which slide bars canmove to unlocked position when said circuit breaker has been moved toits racked out position.

3. In a racking mechanism for circuit breakers; a cubicle for housing acircuit breaker; a racking bar having an opening; a racking screwextending through said opening; a circuit breaker mechanism carryingsaid racking screw and mountable for movement with said racking screw;said racking screw having screw threads engaging with threads in saidopening to permit relative movement of said racking screw and thecircuit breaker with respect to said racking bar when said racking screwis rotated; a slide member for each end of said racking bar, each slidemember having a slotted end; a bolt extending from each end of saidracking bar into the slot of the adjacent slide member; a three-waycrank mounted adjacent one of said slide members, said crank having alock and unlock position and a pair of bifurcated crank extensionsthereon, a pin connected to said one of said slide members and extendingthrough one of the bifurcated crank extensions, a connecting rodconnected at one end of the other of said slide members and having a pinat its other end extending through the other of said pair of bifurcatedcranks, said three-way crank when rotated causing movement of said slidebars in a direction longitudinally of said racking bars, said slide barsmoving in opposite directions; a pin extending from each of said slidebars; an anchor formed in said cubicle walls for screwing said slidemember pins when they are in extended lock position for anchoring saidracking bar; downwardly extending flanges mounted on said circuitbreaker, said flanges being in the path of movement of said slidemembers, said flanges having slots through which slide bars can move tounlocked position when said circuit breaker has been moved to its rackedout position, and a flange on said cubicle for preventing entry of saidcircuit breaker into said cubicle while said slide members are inextended or locked position.

4. In a racking mechanism for circuit breakers; a cubicle for housing acircuit breaker; a racking bar having an opening; a racking screwextending through said opening; a circuit breaker mechanism carryingsaid racking screw and 9 mountable for movement with said racking screw;said racking screw having screw threads engaging with threads in saidopening to permit relative movement of said racking screw and thecircuit breaker with respect to said racking bar when said racking screwis rotated; a slide member for each end of said racking bar, each slidemember having a slotted end; a, bolt extending from each end of saidracking bar into the slot of the adjacent slide member; a three-waycrank mounted adjacent one of said slide members, said crank having alock and unlock position and a pair of bifurcated crank extensionsthereon, a pin connected to said one of said slide members and extendingthrough one of the bifurcated crank extensions, a connecting rodconnected at one end of the other of said slide members and having a pinat its other end extending through the other of said pair of bifurcatedcranks, said three-way crank when rotated causing movement of said slidebars in a direction longitudinally of said racking bars, said slide barsmoving in opposite directions; a pin extending from each of said slidebars; an anchor formed in said cubicle walls for screwing said slidemember pins when they are in extended lock position for anchoring saidracking bar; downwardly extending flanges mounted on said circuitbreaker, said flanges being in the path of movement of said slidemembers, said flanges having slots through which slide bars can move tounlocked position when said circuit breaker has been moved to its rackedout position.

5. In a racking mechanism for circuit breakers, a cubicle for housing acircuit breaker; a racking bar having an opening having internalthreads, a racking screw extending through said opening, a circuitbreaker carrying said racking screw and mounted for movement with saidracking screw, said racking screw having threads engaging with threadsin said racking bar opening to permit relative movement of racking screwand circuit breaker with respect to said racking bar when said rackingscrew is rotated; a lock member connected to said racking bar; a handlefor moving said lock member to a lock and unlock position, an anchor onsaid cubicle for receiving said lock member when moved to its lockposition for anchoring said racking bar in said cubicle to permitmovement of said circuit breaker into and out of said cubicle, a membermounted on said circuit breaker for preventing movement of said lockmember while said circuit breaker is in its racked-in position relativeto said racking bar and permitting movement of said lock member whensaid circuit breaker is in its racked-out position relative to saidracking bar, and a member on said cubicle for preventing entry of saidcircuit breaker in said cubicle when said lock member is in its lockedposition.

6. In a racking mechanism for circuit breakers, a cubicle for housing acircuit breaker; a racking bar having an opening having internalthreads, a racking screw extending through said opening, a circuitbreaker carrying said racking screw and mounted for movement with saidracking screw, said racking screw having threads engaging with threadsin said racking bar opening to permit relative movement of racking screwand circuit breaker with respect to said racking bar when said rackingscrew is rotated; a lock member connected to said racking bar; a handlefor moving said lock member to a lock and unlock position, an anchor onsaid cubicle for receiving said lock member when moved to its lockposition for anchoring said racking bar in said cubicle to permitmovement of said circuit breaker into and out of said cubicle, a membermounted on said circuit breaker for preventing movement While saidcircuit breaker in its relative position with respect to said rackingbar corresponds to its racked-in position in said cubicle and forpermitting movement of said lock member when said circuit breakerposition with respect to said racking bar corresponds to its racked-outposition.

7. In a racking mechanism for circuit breakers, a cubicle for housing acircuit breaker, a racking bar, a racking member movable with respect tosaid racking bar, a circuit breaker carrying said rackin member andmovable therewith relative to said racking bar, a slide member for eachend of said racking bar, each slide member having a slotted end, a boltextending from each end of said racking bar into the slot of theadjacent slide member; a three way crank mounted adjacent one of saidslide members, said crank having a lock and unlock position and a pairof bifurcated crank extensions thereon, a pin connected to said one ofsaid slide members and extending through one of the bifurcated crankextensions, a connecting rod connected at one end of the other of saidslide members and having a pin at its other end extending through theother of said pair of bifurcated cranks, said three way crank whenrotated causing movement or said slide bars in a directionlongitudinally of said racking bar, said slide bars moving in oppositedirections, a pin extending from each of said slide bars; a bearingmounted on the side Walls of said cubicle for receiving said slidemember pins when said slide bars have been moved longitudinally awayfrom said racking bar in response to the rotation of said three-waycrank to its locked position; said pins when extended into said bearingsacting to anchor said racking bar so that when said screw is rotated,said screw and the circuit breaker carrying said screw is moved relativeto said racking bar and cubicle; downwardly extending flanges mounted onsaid circuit breaker, said flanges being in the path of movement of saidslide members; said flanges having slots through which slide bars canmove to unlocked position when said circuit breaker has been moved toits racked out position, and a flange on said cubicle for preventingentry of said circuit breaker into said cubicle while said slide membersare in extended or locked position.

8. In a racking mechanism for circuit breakers, a cubicle for housing acircuit breaker; a racking bar having an opening; a racking screwextending through said opening; a circuit breaker mechanism carryingsaid racking screw and mountable for movement with said racking screw;said racking screw having screw threads engaging with threads in saidopening to permit relative movement of said racking screw and thecircuit breaker with respect to said racking bar when said racking screwis rotated; a slide member for each end of said racking bar, each slidemember having a slotted end; a bolt extending from each end of saidracking bar into the slot of the adjacent slide member; a three-waycrank mounted adjacent one of said slide members, said crank having alock and unlock position and a pair of bifurcated crank extensionsthereon, a pin connected to said one of said slide members and extendingthrough one of the bifurcated crank extensions, a connecting rodconnected at one end of the other of said slide members and having a pinat its other end extending through the other of said pair of bifurcatedcranks, said three way crank when rotated causing movement of said slidebars in a direction longitudinally of said racking bars said slide barsmoving in opposite directions; a pin extending from each of said slidebars; a bearing mounted on the side walls of said cubicle for receivingsaid slide member pins when said slide bars have been movedlongitudinally away from said racking bar in response to the rotation ofsaid three-way crank to its locked position; said pins when extendedinto said bearings acting to anchor said racking bar so that when saidscrew is rotated, said screw and the circuit breaker carrying said screwis moved relative to said racking bar and cubicle; a member mounted onsaid circuit breaker for preventing movement of slide members to itsunlock position while said circuit breaker in its relative position withrespect to said racking bar corresponds to its racked-in position insaid cubicle and for permitting movement of said slide members when saidcircuit breaker position with respect to said racking bar corresponds toits racked-out position, and a member on said cubicle for preventingentry of said circuit breaker in said cubicle when said slide member isin its locked position.

9. In a racking mechanism for circuit breakers, a cubicle for housing acircuit breaker; a racking bar having an opening having internalthreads, a racking screw extending through said opening, a circuitbreaker carrying said racking screw and mounted for movement with saidracking screw, said racking screw having threads en- 12 gaging withthreads in said racking bar opening to permit relative movement ofracking screw and circuit breaker with respect to said racking bar whensaid racking bar is rotated; a lock member connected to said rackingbar; a handle for moving said lock member to a lock and unlock position,an anchor on said cubicle for receiving said lock member when moved toits lock position for anchoring said racking bar in said cubicle topermit movement of said circuit breaker into and out of said cubicle, amovable member, means including said movable member for preventingmovement of said lock member while said circuit breaker is in itsracked-in position relative to said racking bar and permitting movementof said lock member when said circuit breaker is in its racked-outposition relative to said racking bar, and a member on said cubicle forpreventing entry of said circuit breaker in said cubicle when said lockmember is in its locked position.

ARTHUR S. CASWELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED sTATEs PATENTS Number Name Date 1,706,114 Gordon Mar. 19, 19291,729,864 Brown Oct. 1, 1929 2,273,002 Mahoney Feb. 10, 1942 2,544,314Hebbel Mar. 6, 1951 2,554,510 Spicer May 29, 1951

